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Water Molecule consists of 2 atoms of hydrogen 1 atom of oxygen joined together in a covalent bond atoms share e in outer shells The water molecule is dipolar because the 2 H atoms

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Water Molecule consists of 2 atoms of hydrogen 1 atom of oxygen joined together in a covalent bond atoms share e in outer shells The water molecule is dipolar because the 2 H atoms Powered By Docstoc
					Water Molecule
       - consists of 2 atoms of hydrogen & 1 atom of oxygen joined together in a covalent bond
(atoms share e- in outer shells)

The water molecule is dipolar because the 2 H atoms join the O atom at ~105° angle (104°31’).
Due to this polar nature, water molecules form hydrogen bonds between each other via
electrostatic forces

These polar molecules bind together in complexes & can reduce the intensity of an electrical
field to 1/80 th of their value. Ions can dissociate easier so water is the universal solvent

Physical Properties of Water
1) high boiling point (100°C) & high melting point (0°C)
2) very high Heat of Vaporization (540 cal/g) - cooling process for animals & plants
3) extremely high heat capacity - ability to store heat; thus water heats & cools more slowly &
        thereby prevents extreme climatic temperature change
4) superior solvent
5) very low viscosity
6) extremely high surface tension (cohesion) & an even higher wetting ability (adhesion)
7) only common substance that expands rather than contracts when freezes starting at 4°C;  =
        1g/cm3

Water is the only substance on Earth that appears in all three states - solid, liquid, gaseous

States of Water
solid - vibration is the dominant type of molecular motion
liquid - vibration, rotation & translation; but the molecules are still attracted to each other
gaseous - translation is the dominant type of molecular movement & there is no attraction
        between molecules

Phase Changes from One State to Another
1) melting & freezing - between solid & liquid
2) condensation & evaporation - between liquid & gaseous
3) sublimation - between solid & gaseous

When water changes from one state to another, heat energy (latent heat) is either absorbed or
released with no change in temperature

				
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posted:11/27/2011
language:English
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